This application is directed to the field of fiber optic lighting and in particular to an improved fiber optic light bar and method of manufacturing the same.
It is well known in the art to utilize a fiber optic device as a light source. A fiber optic light bar is a known structure having a frame with a plurality of openings formed therein, with a plurality of fiber optic cables disposed within the frame and having their ends positioned within the openings. As used herein, the term cable is meant to include a single fiber or a group of fibers. The lengths of the fiber optic cables are contained within the frame and exit the frame as a single bundle, preferably at one end of the frame. The fiber optic cable bundle extends to a remote location where a light source provides light energy to input ends of the plurality of fiber optic cables. The light travels through the bundle and exits the plurality of fiber optic cables at the outlet ends disposed within the frame.
Fiber optic light bars are known to have many uses, for example, as a light source for a merchandise display case. The frame of the light bar may be attached to an upper portion of the display case with the outlet ends of the fiber optic cables directed downward toward the merchandise. The fiber optic cable bundle is routed along the frame of the display case to the location of a remote light source. It is known in the art to utilize an incandescent light source to provide light energy to the input ends of the fiber optic cables of a fiber optic light bar. The light produced by such a light source is white light. U.S. Pat. No. 5,528,714 issued to Kingston, et al. and assigned to the assignee of the present invention, describes a color wheel that may be utilized with a fiber optic light bar to provide multicolored lighting from a fiber optic light source.
Prior art fiber optic light bars are expensive to manufacture because known manufacturing techniques are labor intensive. Light bars are produced by drilling multiple holes in the surface of a plastic, glass or metal housing, and then placing individual fibers of a desired length in the predrilled holes by a manual operation. The fibers are secured in the predrilled holes and the ends of the cables are cut flush to the surface of the housing. The plurality of fibers in the surface are then routed through the housing to one end where they are formed into a bundle to exit the housing.
There have been previous attempts to automate the production of a fiber optic light bar. One such attempt is U.S. Pat. No. 5,430,825 issued to Leaman, wherein a plurality of fiber optic strands is drawn between a pair of spaced apart insert sections having semicircular gaps designed to fit each of the fiber optic strands in a circular opening when the inserts are brought together. The applicants have found that this and other prior art techniques do not result in a sufficiently low manufacturing cost for some applications of a fiber optic light bar. Furthermore, the applicants desire a fiber optic light bar having improved flexibility for providing advanced lighting effects for a display case application.
In light of the limitations of the prior art, it is an object of this invention to provide an improved manufacturing process for a fiber optic light bar. It is a further object of this invention to provide a manufacturing process for a fiber optic light bar that requires a reduced amount of manual labor. It is a further object of this invention to provide a low cost fiber optic light bar. It is a further object of this invention to provide a fiber optic light bar having improved capabilities for providing multi-color lighting effects.
Accordingly a fiber optic light bar is provided having a fiber optic light bar comprising: a plurality of spacers, each spacer having a top surface and an opposed bottom surface, the plurality of spacers joined together to form a linear array wherein the plurality of top surfaces adjoin the plurality of bottom surfaces of respective adjacent spacers; a groove formed in a central portion of the respective top surfaces of each of the spacers, the grooves forming a plurality of passages from a front surface to a back surface of the linear array; a plurality of fiber optic cables disposed in the respective plurality of passages, each fiber optic cable having an end disposed adjacent the front surface and having a length extending beyond the back surface; each spacer further comprising wall members extending rearward beyond the central portion of the top surface to form a channel along the back surface of the linear array; the plurality of lengths of the plurality of fiber optic cables being disposed within the channel.